Arrangement on a loom for monitoring the weft insertion member

ABSTRACT

An arrangement for use in a loom for monitoring the movement of a weft insertion member, e.g., a shuttle which comprises means for producing two transit signals during movement of the shuttle through the loom, the time interval between the signals being dependent upon the speed of the shuttle, and a device actuated by these signals for performing a preset monitoring operation. This device produces an indication which occurs at the end of the completion of the preset operation, is so actuated by the signals that the first transit signal initiates the preset operation, and the second signal interrupts the preset operation, and allows the duration of the preset operation to be variable.

Q Unlted States Patent 1111 3,565,126

[72] Inventor RudolfSchlappi [56] ReferenoesCited 1N 'gg z agg hswitzerland UNITED STATES PATENTS 2,981,296 4/1961 Pauletal. 139/341 [22] PM 3,181,573 5/1965 Stutz 139/341 [45] Patented Feb. 23, 1971 [73] Assignee Ruti Machinery Works Ltd.

Ruti, Zurich Switzerland [32] Priority Feb. 16, 1968 [33] Switzerland 1 [54] ARRANGEMENT ON A LOOM FOR MONITORING 3,373,773 3/1968 Balentineetal.

Primary Examiner- Henry S. Jaudon Attorneys-Donald D. Benton and David T. Terry operation, is so actuated by the signalsthat the first transit signal initiates the preset operation, andthe second signal interrupts the preset operation, and allows the duration of the preset operation to be variable.

ARRANGEMENT ON A LOOM FOR MONITORING'IIIE WEFT INSERTION MEMBER This invention relates to an arrangement for use in a loom for monitoring the movement of the weft insertion member. More particularly, this invention relates to an arrangement having means for generating two transit signals during the movement of the insertion member, e.g., a shuttle, along its flip-flop circuitsis connected to'a "gate" circuit, the conduct- .ing or nonconducting action of which is controlled in dependence upon the time of occurrence of the signals generated by the shuttle.

Advantageously, the present invention provides a'rnonitoring arrangement for a weft insertion member which is of simplecons'truction and'in which the measurement of the time spacing of the two signals generated by. the movement of the insertion member takes place as directly as possible.

Moreover, the arrangement of this invention affords ,rnirtimum susceptibility to breakdown and high accuracy 'of measurement. In addition, use of this'arrangement allows simple adaptation to different operating conditions such as, for example, different weaving breadths and operating speeds of the loom.

Thus, this invention contemplates an arrangement for use in a loom for rnonitoring the movement of a shuttle on a path through the loom which'comprisesa'first means for generating two transit signals during movement of the shuttle through the loom, the time interval or spacing between the signals being dependent on and being indicative of the speed of the shuttle, and a second means or device to which the signals are applied and which is actuated by the signals for performing a preset monitoring or control operation; the arrangement further being characterized in that the preset operation includes the production of an indication which'occurs at the end of the completion of the preset operation, in that the first of the two transit signals initiates this operation in each instance, in that the second of the two transit signals interrupts this operation in each instance, and in that the duration of the preset operation is variable. More particularly, in accordance with this invention, the second means produces the indication which occurs at the end of the completion of the preset operation, is responsive to the first transit signal whereby the first signal initiates the preset operation, is responsive to the second transit signal whereby the second signal interrupts the preset operation, and allows the duration of the preset operation to be variable.

It will be appreciated that the aforesaid advantages of the present invention are due substantially to the provision of the above-defined operation, because it both serves as a direct measure of the time spacing of the signals and renders possible in a simple manner, by variation thereof, adaptation to different operating conditions.

The invention will now be more fully explained with reference to one of its embodiments and to the accompanying drawings, in which:

FIG. 1 is a diagrammatic side elevation of the left-hand end of the sley of a loom showing a shuttle and the arrangement of the invention particularly the means for generating two transit signals during movement of the shuttle; and

FIG. 2 is a circuit diagram of the arrangement for monitoring the shuttle movement through the loom.

FIG. 1 shows the left-hand side of a sley 1 1. A shuttle or insertion member 14 is periodically shot from left to right by means of the picking stick 12 and the picker 13. One of the swords or sidebars of the heater is denoted by reference numeral l5 and a shuttle box by reference numeral 16.

Provided in the shuttle 14 are two magnets 17 and I8 which are spaced apart in the direction of its length. In addition, an induction coil 19 is provided in the sley 11 near its end. When the shuttle 14 is moved along the sley 11, each of the magnets 17 and 18 generates an alternating voltage (Le, a signal) which is set up between the ends of the coil 19.

In order to evaluate the signals 20 formed by the moving magnets 17, 18 in the coil 19, the circuit arrangement illustrated in FIG. 2 is employed. One end of the coil 19 is coupled to the base of the transistor 22 through the rectifier 21. The other end is connected to earth potential, i.e., ground. The emitter electrode of the transistor 22 is also at earth potential and its collector 23 is connected through a resistor 24 to the positive pole of a voltage source. In addition, the collector 23 is capacitively coupled to the input of a flip-flop circuit. The flip-flop circuit includes the transistors 25 and 26. The base electrode 27 of the transistor 25 is connected to the collector 30 of the transistor 26 through the resistor 28 connected in parallel with the capacitor 29. Likewise, the base electrode 31 of the transistor 26 is connected to the collector electrode 34 of the transistor 25 through the resistor 32 connected in parallel with the capacitor 33. The emitter electrodes 35, 36 of the transistors 25 and 26, respectively, are directly connected to earth potential, while the base electrodes 27, 31 are connected to earth potential through resistors. The signals applied through the capacitor 37 pass to one pole of each of the rectifiers 38 and 39.

The collector 30 of the transistor 26 is connected through the variable resistor 40 to one pole of the capacitor 41, the other pole of which is groundedzT he collector 30 is also connected to the positive pole of the voltage source through the resistor 42. The resistor 40 is bridged by the series connection of the resistor 43 with the rectifier 44. In addition, a series arrangement comprising a rectifier 45 and a second capacitor 46 (which is capacitively coupled through the capacitor 58) is connected in parallel with the capacitor 41.

The potential present in relation to earth across the capacitor 41 is connected to the emitter electrode 66 of the unijunction transistor 47, the base electrodes 48, 49 of which are connected through resistors to the positive pole of the voltage source and to earth (or ground), respectively. The electrode 49 is in addition connected to the input of a controllable diode 50 which operates as a self-holding relay. One rectifier electrode of the diode 50 is connected to one terminal of an indicating instrument constructed as a light source 52 and to one terminal of an electromagnet 53. The magnet serves to stop the loom. The other terminals of the elements 52 and 53 may be selectively connected to the positive pole of the voltage source by the switch 51. When the potential of the emitter electrode 66 of the unijunction transistor 47 reaches a predetermined threshold value, there is set up between the electrodes 66. and 49 a current flow supplied by the capacitor 41, which renders the resistance between these electrodes negative, so that the current rises in avalanche fashion.

In the operation of the weaving loom, the shuttle l4 illustrated in FIG. 1 is propelled to and fro over the sley. When it is moved from left to right (as shown in FIG. 1), one transit signal 20 is first generated in the coil 19 by the magnet 18 and another is then generated. by the magnet 17. The time spacing between these transit signals 20 depends upon the speed of the shuttle 14. The variation of such a transit signal 20 is substantially represented by the curve form shown in FIG. 2. The transit signals 20 generate in the output of the transistor 22 a square wave pulse 54, which is converted into the signal 55 by differentiation by means of the capacitor 37.

When the flip-flop circuit is in the inoperative state, the transistor 26 is conductive and the transistor 25 is nonconductive. The negative peak of the signal-55 consequently has no effect on the transistor 25, but renders the transistor 26 nonconductive. Due to this turning-off of the transistor 26 and thus of the current flow therethrough, the voltage at the collector 30 rises. This voltage rise is transmitted through the elements 28, 29 to the base 27 of the transistor 25, whereby the transistor 25 is rendered conductive. As a result of the current flowing in the collector 34 of the transistor 25, the potential of the latter falls and this potential fall is transmitted through the elements 32, 33 to the base electrode 31, so that the transistor 26 remains in its nonconductive state.

As a result of the nonconductive state of the transistor 26 and the consequent rise of the potential of the collector 30, the capacitor 41 is gradually charged up through the resistor 40. At the time, a fraction of the charging energy thus supplied flows through the capacitor 46, which is connected in parallel with the capacitor 41 through the capacitive coupling formed by the capacitor 58. The charging of the capacitor 41 through the resistor 40 consequently forms a preset operation whose duration is varied by variation of the resistance of resistor 40.

Shortly thereafter a signal is again generated in the coil 19 by the second magnet 17 provided in the shuttle 14. This signal has the same shape as the signal 20 generated by the magnet 18. As in the previously described operation, this signal charges the flip-flop circuit back into its original state of operation, i.e., this signal brings the transistor into its nonconductive state and the transistor 26 into its conductive state. As a result of this new state of operation, the potential of the collector 30 again falls or decreases approximately to earth potential. The operation described in the foregoing therefore requires that the variation of the voltage of the collector 30 is as represented by the wave form of signal 56 as shown in FIG. 2. As the potential of the collector 30 falls towards zero, the capacitor 41 discharges partly through the resistor 40, but substantially through the elements 43, 44 and through the now conducting transistor 26. By suitable choice of the elements 43, 44, the discharge action can be made very short. in order that the coupling capacitor 58 may also discharge, the rectifier 59 is provided to close the discharge path thereof.

When the shuttle 14 moves towards the other end of the sley 11, i.e., in this case towards the right-hand end thereof, it again passes over a coil (not shown) corresponding to the coil 19 and mounted (in the same way as coil 19) at some distance from the right-hand shuttle box. When this happens, there are again set up in the coil situated on the right-hand side of the sley 11 two time signals of the form illustrated for signal 20 in FIG. 2, whereby the circuit arrangement illustrated in FIG. 2 is again caused to operate as heretofore described. The only difference from the first operation resides in that a certain voltage is already present at the capacitor 46. Owing to the blocking action of the rectifier 45, this capacitor 46 has not been discharged during the discharge of the capacitor 41.

When the flip-flop circuit again changes into the active state on the inductive actuation of the coil (not shown) situated on the right-hand side of the sley 11, whereby the transistor 25 becomes conductive and the transistor 26 becomes nonconductive, the capacitor 46 will take up somewhat less charging energy because a small charge is already present in the capacitor, so that the capacitor 41 will be somewhat more rapidly charged than in the previously described passage of the shuttle 14 over the coil 19.

This process is repeated at each passage of the shuttle 11 over the coils, until the capacitor 46 has been charged to a value at which it takes up no further charge. When this state has been reached, the time for charging the capacitor 41 also remains constant. Consequently, the preset operation, consisting in a charging of the capacitor 41, can be varied by the elements 45, 46 connected in parallel with the capacitor 41.

If for any reason the shuttle 14 moves too slowly, the charging of the capacitor continues correspondingly longer, i.e., the capacitor is more highly charged. The threshold value of the unijunction transistor 47 is so chosen that it is reached in this event. If this is the case, the transistor 47 becomes conductive and a current supplied by the charging of the capacitor 41 begins to flow through the transistor 47. This current is an indication which occurs at the end of the preset operation. Due to this current, the potential of the electrode 49 becomes more positive and as a result of this rise of potential, the controllable diode 50 in turn becomes conductive. The current thus flowing through the switch S1 and through the magnet 53 actuates the magnet, which is so arranged that actuation thereof renders a mechanism for stopping the weaving loom operative.

The charging time of the capacitor 41 thus serves as a comparison value for monitoring the time spacing between the time or transit signals 20 and thus the speed of the shuttle 14. Since, as already described, the capacitor 46 extracts, until it has been completely charged, constantly decreasing quantities of charging energy intended for the capacitor 41, the time necessary to reach the threshold value for the charging capacitor 41 is initially greatest. it decreases with increasing charging of the capacitor 46 and approaches a particular end value. The charging time of the capacitor 41 is therefore variable by the parallel-connected elements 45, 46 in the sense that the time is greatest at the starting of the weaving loom and reaches the end value after a predetennined period of operation. This manner of operation has been found very advantageous because a weaving loom runs somewhat more slowly immediately after starting than in the subsequent continuous operation. Therefore, the duration of the charging of the capacitor 41 can be varied by giving the capacitor 46 a suitable value, and may thus be accurately adapted to the starting conditions of the weaving loom. It is desirable that the capacitor 46 should not be discharged simply by fortuitous surface leakage currents at thestopping of the weaving loom, and that its discharge should be effected in controlled manner by a circuit actuated with the stop motion of the weaving loom.

FIG. 2 also illustrates a second manner of varying the duration of the charging of the capacitor 41, namely, by variation of the resistance of the variable resistor 40. When the value of this resistor 40 is increased, the time for charging the capacitor 41 is increased to a predetermined threshold value or desired value; on the other hand, this time is shortened by reduction of the value of resistance of the resistor 40.

The provision of the variable resistor 40 is particularly advantageous in combination with the lamp 52 serving as an indicating instrument, in that this combination affords, in an extremely simple manner, possible adjustment for accurate monitoring of the shuttle. For an accurate adjustment, the switch 51 is connected to the lamp 52 instead of to the magnet 53. Thereafter, the resistor 40 is so varied that the capacitor 41 exactly reaches the threshold value at each passage of the shuttle 14. The unijunction transistor 47 is fired each time this happens, and the lamp 52 is thus lit up in each instance. The resistor 40 is thereafter again varied by a small amount in the sense of an increase in its value, and the switch 51 is changed back to the magnet 53. it is desirable for the resistor 40 employed as regulating member to be provided with a scale which is calibrated in flight times or speeds of the shuttle.

It is apparent from the observations made in the foregoing that the combination of the elements 45, 46 connected in parallel with the capacitor 41 and of the variable resistor 40 affords special advantages. Owing to the slower operation of weaving looms in their starting period, there is a tendency for the monitoring to be set to shuttle speeds which are too slow, because otherwise the possibility exists that the weaving machine will be stopped during the starting period without any actual fault in the operation. This undesirable stopping is avoided by the variation of the charging time of the capacitor 41 by means of the elements 45, 46; moreover, a finer adjustment of the monitoring period is obtained by means of the variable resistor 40 and the lamp 52 than in the arrangements commonly employed.

Of course, too rapid a flight of the shuttle 14 can be observed by switching over to the lamp 52. When this happens, the flight of the shuttle will be correctly adjusted by correspondingly lowering the flight times, so that unnecessarily high wear is avoided.

For the sake of completeness, it will be mentioned that it is also possible for a suitable circuit element other than the resistor 40, for example the capacitor 41, to be made variable. it is likewise possible to employ as the indicating instrument, instead of the optical indication provided by the lamp 52, other means, for example an acoustic indication device.

stops the weaving loom or in addition, it must be borne in-mind that the speed of a shuttle is about 5 percent higher at the beginning of its travel than at the end thereof. The adjustment of the regulating member 40 must naturally be suc'has to control-the speed at the end of the path of travel, so that at the beginning of shuttle travel, a small margin exists for the speed variation. If it is desired to'avoid this, the action of the coils may be'interrupted at the beginning or at the end of the travel of the shuttle 14 by corresponding control in step with the operating cycle of the weaving loom.

Likewise, instead of the two magnets 17 and 18 in the shuttle l4 acting inductively upon a coil 19 provided in the sley 11 (as described), a magnet in the shuttle, for example, may act upon two coils mounted in the sley. Alternatively, a capacitive action may be employed instead of an inductive action. In this case, for example, two capacitors situated at a predetermined distance apart along the sley would be influenced by the shuttle or by an actuating element present in the shuttle in such manner that their capacitance would be varied on travel of the insertion member past them. The signals set up by the capacitance change would then be applied to the circuit arrangement illustrated in FIG. 2.

In the present embodiment, the charging of the capacitor 41 g is utilized for the predetermined. operation. Alternatively, in some cases other action may be utilized to define the time interval. As an example of such an action, there may be mentioned the advance of a step-by-step switch which supplies a signal at each complete revolution andin which the number of steps and/or the speed of operation may be varied. If desired, mechanical,-regulatable movements are possible which, on

, completion, supply an indication, for example in the form of the movement of a member, which, when operated, either dicating instrument.

lclaim:

1. An arrangement for use in a loom for monitoring the movement of a shuttle, comprising'a first means for producing two transit signals during movement of a shuttle on a path through the loom, theftime interval between the signals being dependent upon the speed of the shuttle; and a second means actuated by said signals for 'performinga preset monitoring operation and for producing an indication at the end of said preset monitoring operation, said second means comprising storage means for storing electrical energy; electrical circuit meansresponsiveto said transit signals;,said circuit means, in response to the first transit signal, charging electrical energy to said storage means whereby said preset operation is initiated and, in response to the second transit signal, discharging said storage means whereby said preset operation is interrupted; a signal producing means coupled to said storage means and responsive to the electrical energy stored therein for producing said indication when the electrical energy supplied and stored in said storage means exceeds a given threshold value; and regulating means for varying the speed by which said storage means is charged. I

2. The arrangement of claim 1 in which said second means includes an indicating means to which the indication is applied for indicating completion of the monitoring operation.

3. The arrangement of claim 1 in which the regulating produces 'an indication in an inis in its starting phase, and said indication being applied to the a second capacitor which is coupled to the first capacitor by a coupling which has limited conductivity for the charging energy to be applied to the first capacitor, the discharge arrangement of the second capacitor being inoperative, during the preset operation so that, with successive operations of the arrangement during the starting period of the loom, constantly decreasing amounts of the charging energy to be applied to the first capacitor flow to the second capacitor.

7. The arrangement of claim 1 in which said signal producing means comprises a trigger means coupled to said storage means, said trigger means being so adjusted that when the predetermined threshold value is reached, said trigger means is changed over from one state of operation to another state of operation, the other state of operation serving to produce said control electrode in relation to another of its electrodes, said electrodes being connected in parallel with said capacitor and the capacitor having a voltage equal to this predetermined voltagev on reaching its threshold value.

9. The arrangement of claim 8 in which said transistor is a unijunction transistor which has an emitter electrode that serves as said control electrode and two base electrodes.

10. The arrangement of claim 1 in which said electric circuit means includes a voltage source, two electrical contacts and a switching means, said storage means comprises a first capacitor and said regulating means includes a resistor, said capacitor together with the resistor forming a serigz arrangement situated between said two electrical contacts, one contact being coupled to one pole of the voltage source and the other contact being coupled to the switch means which is controllable in dependence upon the transit signals, whereby said other contact can be selectively electrically connected to said one pole of the voltage source or to ground by said switch means in order to effect charging or discharging of said first capacitor.

11. The arrangement of claim 10 in which said switch means means includes a scale which indicates the extent of the variation of the preset operation and which is calibrated in flight times or speeds of the shuttle.

4. The arrangement of claim 1 in which said circuit means comprises a flip-flop circuit, said flip-flop circuit in one condition successively charging electrical energy to said storage means and in its other condition successively discharging said storage means.

5. The arrangement of claim .1 further comprising means for stopping the loom, the duration of the preset operation being made variable during that period of operation when the loom and a second electrode coupled via the other contact of the series arrangement and through another resistor to said one pole of the voltage source, whereby said 'two electrodes may be conductively and nonconductively connected by the control electrode of the transistor in dependence upon said transit signals.

12. The arrangement of claim 11 in which the switch means is formed by one transistor of a flip-flop circuit comprising two transistors and controllable by the transit signals and the potential of the control electrode of one transistor being changed between two values by the operation of the flip-flop circuit, whereby said one transistor becomes alternately conductive and nonconductive between its emitter electrode and its collector electrode.

13. The arrangement of claim 10 in which the resistor of the series arrangement is a variable resistor.

14. The arrangement of claim 10 in which said regulating means also includes a second capacitor and a rectifier connected in series therewith which are connected in parallel with said first capacitor and are capacitively coupled to said first capacitor, the rectifier being conductive in the forward direction of the current supplied by the voltage source.

15. The arrangement of claim 10 in which said regulating means includes a rectifier coupled in parallel with said resistor, said rectifier conducting in the opposite direction to the charging current supplied by said electrical circuit means. 

1. An arrangement for use in a loom for monitoring the movement of a shuttle, comprising a first means for producing two transit signals during movement of a shuttle on a path through the loom, the time interval between the signals being dependent upon the speed of the shuttle; and a second means actuated by said signals for performing a preset monitoring operation and for producing an indication at the end of said preset monitoring operation, said second means comprising storage means for storing electrical energy; electrical circuit means responsive to said transit signals; said circuit means, in response to the first transit signal, charging electrical energy to said storage means whereby said preset operation is initiated and, in response to the second transit signal, discharging said storage means whereby said preset operation is interrupted; a signal producing means coupled to said storage means and responsive to the electrical energy stored therein for producing said indication when the electrical energy supplied and stored in said storage means exceeds a given threshold value; and regulating means for varying the speed by which said storage means is charged.
 2. The arrangement of claim 1 in which said second means includes an indicating means to which the indication is applied for indicating completion of the monitoring operation.
 3. The arrangement of claim 1 in which the regulating means includes a scale which indicates the extent of the variation of the preset operation and which is calibrated in flight times or speeds of the shuttle.
 4. The arrangement of claim 1 in which said circuit means comprises a flip-flop circuit, said flip-flop circuit in one condition successively charging electrical energy to said storage means and in its other condition successively discharging said storage means.
 5. The arrangement of claim 1 further comprising means for stopping the loom, the duration of the preset operation being made variable during that period of operation when the loom is in its starting phase, and said indication being applied to the means for stopping the loom.
 6. The arrangement of claim 5 in which said storage means comprises a first capacitor and said regulating means includes a second capacitor which is coupled to the first capacitor by a coupling which has limited conductivity for the charging energy to be applied to the first capacitor, the discharge arrangement of the second capacitor being inoperative, during the preset operation so that, with successive operations of the arrangement during the starting period of the loom, constantly decreasing amounts of the charging energy to be applied to the first capacitor flow to the second capacitor.
 7. The arrangement of claim 1 in which said signal producing means comprises a trigger means coupled to said storage means, said trigger means being so adjusted that when the predetermined threshold value is reached, said trigger means is changed over from one state of operation to another state of operation, the other state of operation serving to produce said indication.
 8. The arrangement of claim 7 in which the storage means comprises a capacitor and the trigger means comprises a transisTor which changes from a nonconductive state to a conductive state when a predetermined voltage is present at its control electrode in relation to another of its electrodes, said electrodes being connected in parallel with said capacitor and the capacitor having a voltage equal to this predetermined voltage on reaching its threshold value.
 9. The arrangement of claim 8 in which said transistor is a unijunction transistor which has an emitter electrode that serves as said control electrode and two base electrodes.
 10. The arrangement of claim 1 in which said electric circuit means includes a voltage source, two electrical contacts and a switching means, said storage means comprises a first capacitor and said regulating means includes a resistor, said capacitor together with the resistor forming a series arrangement situated between said two electrical contacts, one contact being coupled to one pole of the voltage source and the other contact being coupled to the switch means which is controllable in dependence upon the transit signals, whereby said other contact can be selectively electrically connected to said one pole of the voltage source or to ground by said switch means in order to effect charging or discharging of said first capacitor.
 11. The arrangement of claim 10 in which said switch means comprises a transistor having one electrode coupled to ground and a second electrode coupled via the other contact of the series arrangement and through another resistor to said one pole of the voltage source, whereby said two electrodes may be conductively and nonconductively connected by the control electrode of the transistor in dependence upon said transit signals.
 12. The arrangement of claim 11 in which the switch means is formed by one transistor of a flip-flop circuit comprising two transistors and controllable by the transit signals and the potential of the control electrode of one transistor being changed between two values by the operation of the flip-flop circuit, whereby said one transistor becomes alternately conductive and nonconductive between its emitter electrode and its collector electrode.
 13. The arrangement of claim 10 in which the resistor of the series arrangement is a variable resistor.
 14. The arrangement of claim 10 in which said regulating means also includes a second capacitor and a rectifier connected in series therewith which are connected in parallel with said first capacitor and are capacitively coupled to said first capacitor, the rectifier being conductive in the forward direction of the current supplied by the voltage source.
 15. The arrangement of claim 10 in which said regulating means includes a rectifier coupled in parallel with said resistor, said rectifier conducting in the opposite direction to the charging current supplied by said electrical circuit means. 